Windows2003-3790/multimedia/opengl/glu/nurbs/core/trimline.cxx
2020-09-30 16:53:55 +02:00

199 lines
4.7 KiB
C++

/**************************************************************************
* *
* Copyright (C) 1992, Silicon Graphics, Inc. *
* *
* These coded instructions, statements, and computer programs contain *
* unpublished proprietary information of Silicon Graphics, Inc., and *
* are protected by Federal copyright law. They may not be disclosed *
* to third parties or copied or duplicated in any form, in whole or *
* in part, without the prior written consent of Silicon Graphics, Inc. *
* *
**************************************************************************/
/*
* trimline.c++ - $Revision: 1.1 $
* Derrick Burns - 1991
*/
#include "glimport.h"
#include "myassert.h"
#include "mystdio.h"
#include "trimline.h"
#include "backend.h"
Trimline::Trimline()
{
size = 0; pts = 0; numverts = 0;
tinterp = &t; binterp = &b;
}
Trimline::~Trimline()
{
if( pts ) delete[] pts;
}
void
Trimline::init( TrimVertex *v )
{
reset();
grow(1);
append(v);
}
inline void
Trimline::grow( long npts )
{
if( size < npts ) {
size = 2 * npts;
if( pts ) delete[] pts;
pts = new TrimVertex_p[size];
}
}
inline void
Trimline::append( TrimVertex *v )
{
assert( numverts != size );
pts[numverts++] = v;
}
void
Trimline::init( long npts, Arc_ptr jarc, long last )
{
jarcl.init( jarc, 0, last );
grow( npts + 2 );
}
inline void
Trimline::swap()
{
TrimVertex *tmp=tinterp;
tinterp=binterp;
binterp=tmp;
}
void
Trimline::getNextPt()
{
*binterp = *jarcl.getnextpt();
}
void
Trimline::getPrevPt()
{
*binterp = *jarcl.getprevpt();
}
/*----------------------------------------------------------------------
* getNextPts - make arrays of pointers to trim points on left and right
* hulls of trim strip.
*----------------------------------------------------------------------
*/
void
Trimline::getNextPts( REAL vval, Backend& backend )
{
reset(); swap(); append( tinterp );
assert( tinterp->param[1] >= vval );
register TrimVertex *p;
for( p=jarcl.getnextpt() ; p->param[1] >= vval; p=jarcl.getnextpt() ) {
append( p );
}
/* compute and copy pointer to final point on left hull */
if( interpvert( last(), p, binterp, vval ) ) {
binterp->nuid = p->nuid;
backend.triangle( p, binterp, last() );
append( binterp );
}
jarcl.reverse();
(void) jarcl.getprevpt(); /* reset jarcl to proper position */
jarcl.reverse();
}
void
Trimline::getPrevPts( REAL vval, Backend& backend )
{
reset(); swap(); append( tinterp );
assert( tinterp->param[1] >= vval );
register TrimVertex *q;
for( q=jarcl.getprevpt(); q->param[1] >= vval; q=jarcl.getprevpt() ) {
append( q );
}
/* compute and copy pointer to final point on right hull */
if( interpvert( q, last(), binterp, vval ) ) {
binterp->nuid = q->nuid;
backend.triangle( last(), binterp, q );
append( binterp );
}
jarcl.reverse();
(void) jarcl.getnextpt(); /* reset jarcl to proper position */
jarcl.reverse();
}
void
Trimline::getNextPts( Arc_ptr botarc )
{
reset(); swap(); append( tinterp );
PwlArc *lastpwl = botarc->prev->pwlArc;
TrimVertex *lastpt1 = &lastpwl->pts[lastpwl->npts-1];
TrimVertex *lastpt2 = botarc->pwlArc->pts;
register TrimVertex *p = jarcl.getnextpt();
for( append( p ); p != lastpt2; append( p ) ) {
assert( p != lastpt1 );
p = jarcl.getnextpt();
}
}
void
Trimline::getPrevPts( Arc_ptr botarc )
{
reset(); swap(); append( tinterp );
PwlArc *lastpwl = botarc->prev->pwlArc;
TrimVertex *lastpt1 = &lastpwl->pts[lastpwl->npts-1];
TrimVertex *lastpt2 = botarc->pwlArc->pts;
register TrimVertex *q = jarcl.getprevpt();
for( append( q ); q != lastpt1; append( q ) ) {
assert( q != lastpt2 );
q = jarcl.getprevpt();
}
}
long
Trimline::interpvert( TrimVertex *a, TrimVertex *b, TrimVertex *c, REAL vval )
{
REAL denom = a->param[1] - b->param[1];
if(denom != 0) {
if( vval == a->param[1] ) {
c->param[0] = a->param[0];
c->param[1] = a->param[1];
c->nuid = a->nuid;
return 0;
} else if( vval == b->param[1] ) {
c->param[0] = b->param[0];
c->param[1] = b->param[1];
c->nuid = b->nuid;
return 0;
} else {
REAL r = (a->param[1] - vval)/denom;
c->param[0] = a->param[0] - r * (a->param[0] - b->param[0]);
c->param[1] = vval;
return 1;
}
} else {
c->param[0] = a->param[0];
c->param[1] = a->param[1];
c->nuid = a->nuid;
return 0;
}
}